isnice Posted January 5, 2011 Share Posted January 5, 2011 Still shows the norlun feature. Not sure what you are complaining about. Did I ever say it wouldn't? No... I said that the NAM looks like it took a shift towards the GGEM and Euro, which it did. The jackpot is now centered over SE NY and SW CT. Before, it was more northeastern NJ and NYC. But, like NJWinter23 said, the trough placement is going to shift much more. Norluns are so difficult to pinpoint this far out (as we have already reiterated), and therefore we can't really make a call until tomorrow evening. One thing is for sure- it's ridiculous for these forecasters to be calling 3-6" for the city as of now. Link to comment Share on other sites More sharing options...
A-L-E-X Posted January 5, 2011 Share Posted January 5, 2011 yeah its very good for you guys this run, 0.50-.0.75 so far for most of LI This is from Jer: qpf max appears to be LI/S NY just north and east of NYC as well as SW CT. 2NDRY max a good chunk of ME above PWM Link to comment Share on other sites More sharing options...
NorEaster27 Posted January 5, 2011 Share Posted January 5, 2011 If I was forecasting for NYC I would be calling for 1-3. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 5, 2011 Share Posted January 5, 2011 By the way since most of you NYC guys are waiting on this inverted trough is there anyone who can describe the dynamics of what happens? Having a tough time finding a nice concise explanation. I know it somehow provides good lift and snowfall rates but don't know the details. Link to comment Share on other sites More sharing options...
jm1220 Posted January 5, 2011 Share Posted January 5, 2011 yeah its very good for you guys this run, 0.50-.0.75 so far for most of LI Temps will be right at or maybe even above freezing on LI as long as winds are coming out of the east. So it's hard to assume ratios are any greater than 10-1. Link to comment Share on other sites More sharing options...
SACRUS Posted January 5, 2011 Share Posted January 5, 2011 18z NAm NJ/NYC i-195 and south : 0.10 - 0.25 (less south) i-195 and north to i-80/ NYC : 0.25 - 0.50. (more north) Link to comment Share on other sites More sharing options...
A-L-E-X Posted January 5, 2011 Share Posted January 5, 2011 JM why is there such a narrow band of snow with these things? Has there been any cases where any of these have blossomed up to create a more widespread area of heavier snow? Link to comment Share on other sites More sharing options...
Rainshadow Posted January 5, 2011 Share Posted January 5, 2011 It should and I think it is signaling the potential magnitude of the mesoscale features. But in terms of exact placement of the jackpot of this event 60hrs out, it will keep flipping around, and that's why no one should get excited in my opinion until its snowing outside their window Someone should put this post in the thread title. Link to comment Share on other sites More sharing options...
am19psu Posted January 5, 2011 Share Posted January 5, 2011 By the way since most of you NYC guys are waiting on this inverted trough is there anyone who can describe the dynamics of what happens? Having a tough time finding a nice concise explanation. I know it somehow provides good lift and snowfall rates but don't know the details. You might want to ask the SNE folks, since they are more familiar. Here is my take anyway: an upper level jet streak/vort max provides broad divergence aloft over an existing weak boundary located to the northwest of a deepening surface low (such as a coastal front) dropping the pressures along the weak boundary and enhancing convergence at the surface. That produces an inverted trough which enhances convergence further at the surface and allows weak convective enhancement. I'm pretty sure there is a thermal advection part I'm missing, but that should get you started. Link to comment Share on other sites More sharing options...
tmagan Posted January 5, 2011 Share Posted January 5, 2011 By the way the new HPC heavy snowfall maps are out which put Boston in pretty high chances considering no model is giving them heavy snowfall. Link to comment Share on other sites More sharing options...
simpsonsbuff Posted January 5, 2011 Share Posted January 5, 2011 I like the county map because a few miles here or there can make a difference. It would seem from the Bronx northward is the .50+ band extending into the Hudson Valley (where the lollipop is), and then the .50 band from northeast Queens and most of LI. Of course, this will shift around from run to run... Link to comment Share on other sites More sharing options...
ag3 Posted January 5, 2011 Share Posted January 5, 2011 18z NAm NJ/NYC i-195 and south : 0.10 - 0.25 (less south) i-195 and north to i-80/ NYC : 0.25 - 0.50. (more north) NYC is close to or in the .50" line. Last night you posted that 0z GFS was .4" for NYC and the soundings were .79" NYC is on the northern part of western LI. LGA is definitely in the .50"-.75" on NAM also. Link to comment Share on other sites More sharing options...
NorEaster27 Posted January 5, 2011 Share Posted January 5, 2011 Very nice run for the catskill ski areas. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 5, 2011 Share Posted January 5, 2011 You might want to ask the SNE folks, since they are more familiar. Here is my take anyway: an upper level jet streak/vort max provides broad divergence aloft over an existing weak boundary located to the northwest of a deepening surface low (such as a coastal front) dropping the pressures along the weak boundary and enhancing convergence at the surface. That produces an inverted trough which enhances convergence further at the surface and allows weak convective enhancement. I'm pretty sure there is a thermal advection part I'm missing, but that should get you started. Hey that's great, thanks! Understanding a little bit more about what is going on will make it more fun to track, albeit from snowless DC. Link to comment Share on other sites More sharing options...
Stormlover74 Posted January 5, 2011 Share Posted January 5, 2011 Doesnt he say NYC is in the .25-.5? NYC is close to or in the .50" line. Last night you posted that 0z GFS was .4" for NYC and the soundings were .79" NYC is on the northern part of western LI. LGA is definitely in the .50"-.75" on NAM also. Link to comment Share on other sites More sharing options...
simpsonsbuff Posted January 5, 2011 Share Posted January 5, 2011 Doesnt he say NYC is in the .25-.5? Just look at the county chart, I posted... It takes out the guesswork to a large degree. KNYC is pretty much at 0.50. Link to comment Share on other sites More sharing options...
SACRUS Posted January 5, 2011 Share Posted January 5, 2011 NYC is close to or in the .50" line. Last night you posted that 0z GFS was .4" for NYC and the soundings were .79" NYC is on the northern part of western LI. LGA is definitely in the .50"-.75" on NAM also. Not sure which post, maybe you confused with the 00z nam. Not that it matters. I know pretty well where NYC is, and they are near the 0.50 line as was in the range. The key thing here is the consistent signal for this stripe of qpf max is in the general N-NJ, S-NY CT area on most guidance. As other said it'll take more time before a better handle on guidance to hone in on the area and even then this will be a real-time tracking scenario. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 5, 2011 Share Posted January 5, 2011 By the way since most of you NYC guys are waiting on this inverted trough is there anyone who can describe the dynamics of what happens? Having a tough time finding a nice concise explanation. I know it somehow provides good lift and snowfall rates but don't know the details. http://www.weatheranswer.com/public/NORLUN2.pdf Link to comment Share on other sites More sharing options...
NorthShoreWx Posted January 5, 2011 Share Posted January 5, 2011 Very nice run for the catskill ski areas. 12"+ for just about all of the Catskills. They will have good ratios. 1.25" QPF bullseye on Slide Mtn. Link to comment Share on other sites More sharing options...
Collegestudent11 Posted January 5, 2011 Share Posted January 5, 2011 Here is the Mt Holly snow map. A general 4-6 inches across the area. Link to comment Share on other sites More sharing options...
Parsley Posted January 5, 2011 Share Posted January 5, 2011 Here is the Mt Holly snow map. A general 4-6 inches across the area. actually 1-3" for 65-70% of the PHI NWS area..........that looks about right at this time. Good map based on all the models thus far. Link to comment Share on other sites More sharing options...
Bilas Posted January 5, 2011 Share Posted January 5, 2011 I am no expert but these totals are going to change we probably won't know for sure who will get the most snow until very close to the actual start times. Link to comment Share on other sites More sharing options...
supermeh Posted January 5, 2011 Share Posted January 5, 2011 Does upton have a snow map like mt holly? Link to comment Share on other sites More sharing options...
Collegestudent11 Posted January 5, 2011 Share Posted January 5, 2011 actually 1-3" for 65-70% of the PHI NWS area..........that looks about right at this time. Good map based on all the models thus far. You are correct for the PHL area, i was stating the Middlesex County and North. Link to comment Share on other sites More sharing options...
Collegestudent11 Posted January 5, 2011 Share Posted January 5, 2011 Does upton have a snow map like mt holly? Yes, however, it is not avaliable yet. Link to comment Share on other sites More sharing options...
tombo82685 Posted January 5, 2011 Share Posted January 5, 2011 heres the rgem at hr 48, since i think i saw someone said the rgem does well with these setups Link to comment Share on other sites More sharing options...
supermeh Posted January 5, 2011 Share Posted January 5, 2011 Yes, however, it is not avaliable yet. Thanks. Link to comment Share on other sites More sharing options...
eduggs Posted January 5, 2011 Share Posted January 5, 2011 The RGEM lines up nicely with the NAM. Regardless of QPF, there should be at least a 24 hour period where bursts of moderate or heavy snow are possible almost anywhere across the area. Definitely an impressive signal for very isolated high intensity precip. Link to comment Share on other sites More sharing options...
tombo82685 Posted January 5, 2011 Share Posted January 5, 2011 heres the rgem at hr 48 color maps to see it easier Link to comment Share on other sites More sharing options...
easternsnowman Posted January 5, 2011 Share Posted January 5, 2011 The RGEM lines up nicely with the NAM. Regardless of QPF, there should be at least a 24 hour period where bursts of moderate or heavy snow are possible almost anywhere across the area. Definitely an impressive signal for very isolated high intensity precip. Looks like a couple of inches for philly area and 4 + for nyc area. Link to comment Share on other sites More sharing options...
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